Oracle Certification Interview Questions & Answers

Below we have listed all the Oracle Certification Interview Questions and answers. Feel free to comment on any Oracle Certification Interview Questions or answer by the comment feature available on the page.

The Oracle Certified Associate (OCA) credential is the first step toward achieving an Oracle Certified Professional certification. The OCA credential ensures a candidate is equipped with fundamental skills, providing a strong foundation for supporting Oracle products.
The Oracle Certification Program is a professional certification program by Oracle Corporation. Three levels of certification are offered in several disciplines, namely: Oracle Certified Associate (OCA), Oracle Certified Professional (OCP), and Oracle Certified Master (OCM).

DELETE FROM sales;There are no other uncommitted transactions on the SALES table.Which statement is true about the DELETE statement?A. It would not remove the rows if the table has a primary keyB. It removes all the rows as well as the structure of the tableC. It removes all the rows in the table and deleted rows can be rolled backD. It removes all the rows in the table and deleted rows cannot be rolled back

Which two statements are true regarding single row functions? (Choose two.)A. They accept only a single argumentB. They can be nested only to two levelsC. Arguments can only be column values or constantD. They always return a single result row for every row of a queried tableE. They can return a data type value different from the one that is reference

Which two statements are true regarding constraints? (Choose two.)A. A foreign key cannot contain NULL valuesB. A columns with the UNIQUE constraint can contain NULL valuesC. A constraint is enforced only for the INSERT operation on a tableD. A constraint can be disabled even if the constraint column contains dataE. All constraints can be defined at the column level as well as the table level

You need to calculate the number of days from 1st Jan 2007 till date:Dates are stored in the default format of dd-mm-rr.Which two SQL statements would give the required output? (Choose two.)A. SELECT SYSDATE - '01-JAN-2007' FROM DUALB. SELECT SYSDATE - TO_DATE('01/JANUARY/2007') FROM DUAL;C. SELECT SYSDATE - TO_DATE('01-JANUARY-2007) FROM DUAL;D. SELECT TO_CHAR(SYSDATE,'DD-MON-YYYY')-'01-JAN-2007' FROM DUAL;E. SELECT TO_DATE(SYSDATE,'DD/MONTH/YYYY')-'01/JANUARY/2007' FROM DUAL;

When does a transaction complete? (Choose all that apply.)A. When a DELETE statement is executedB. When a ROLLBACK command is executedC. When a PL/SQL anonymous block is executedD. When a data definition language statement is executedE. When a TRUNCATE statement is executed after the pending transaction

Which two statements are true regarding single row functions? (Choose two.)A. They accept only a single argumentB. They can be nested only to two levelsC. Arguments can only be column values or constantD. They always return a single result row for every row of a queried tableE. They can return a data type value different from the one that is reference

Which three statements are true regarding the data types in Oracle Database 10g/11g? (Choosetwo.)A. Only One LONG column can be used per tableB. A TIMESTAMP data type column stores only time values with fractional secondsC. The BLOB data type column is used to store binary data in an operating system fileD. The minimum column width that can be specified for a VARCHAR2 data type column is oneE. The value for a CHAR data type column is blanked-padded to the maximum defined columnwidth

Which statements are correct regarding indexes? (Choose all that apply.)A. When a table is dropped, the corresponding indexes are automatically droppedB. A FOREIGN KEY constraint on a column in a table automatically creates a nonunique keyC. A nondeferrable PRIMARY KEY or UNIQUE KEY constraint in a table automatically creates aunique indexD. For each data manipulation language operation performed, the corresponding indexes areautomatically updated

Which two statements are true regarding views? (Choose two.)A. A subquery that defines a view cannot include the GROUP BY clauseB. A view is created with the subquery having the DISTINCT keyword can be updatedC. A view that is created with the subquery having the pseudo column ROWNUM keyword cannotbe updatedD. A Data Manipulation Language (DML) operation can be performed on a view that is createdwith the subquery having all the NOT NULL columns of a table

Which two statements are true regarding working with dates? (Choose two.)A. The default internal storage of dates is in the numeric formatB. The default internal storage of dates is in the character formatC. The RR date format automatically calculates the century from the SYSDATE function and doesnot allow the user to enter the centuryD. The RR date format automatically calculates the century from the SYSDATE function but allowsthe user to enter the century if required

Which two statements are true regarding working with dates? (Choose two.)A. The default internal storage of dates is in the numeric formatB. The default internal storage of dates is in the character formatC. The RR date format automatically calculates the century from the SYSDATE function and doesnot allow the user to enter the centuryD. The RR date format automatically calculates the century from the SYSDATE function but allowsthe user to enter the century if required

Which two statements are true about sequences created in a single instance database? (Choosetwo.)A. The numbers generated by a sequence can be used only for one tableB. DELETE <sequencename> would remove a sequence from the databaseC. CURRVAL is used to refer to the last sequence number that has been generatedD. When the MAXVALUE limit for a sequence for reached, you can increase the MAXVALUE limitby using the ALTER SEQUENCE statementE. When a database instance shuts down abnormally, the sequence numbers that have beencached but not used would be available once again when the database instance is restarted

Which two statements are true regarding views? (Choose two.)A. A subquery that defines a view cannot include the GROUP BY clauseB. A view is created with the subquery having the DISTINCT keyword can be updatedC. A view that is created with the subquery having the pseudo column ROWNUM keyword cannotbe updatedD. A Data Manipulation Language (DML) operation can be performed on a view that is createdwith the subquery having all the NOT NULL columns of a table

You need to generate a list of all customer last names with their credit limits from theCUSTOMERS table. Those customers who do not have a credit limit should appear last in the list.Which two queries would achieve the required result? (Choose two.)A. SELECT cust_last_name,cust_credit_limitFROM customersORDER BY cust_credit_limit DESC;B. SELECT cust_last_name,cust_credit_limitFROM customersORDER BY cust_credit_limit;C. SELECT cust_last_name,cust_credit_limitFROM customersORDER BY cust_credit_limit NULLS LAST;D. SELECT cust_last_name,cust_credit_limitFROM customersORDER BY cust_last_name,cust_credit_limit NULLS LAST;